Resins for photoresist for use in fabricating processes of semiconductors must have the following functions. Specifically, they must adhere to substrates, be eliminated by action of an acid generated from a photosensitive acid generator with exposure and become soluble in basic developing solutions, and be resistant to dry etching. Increasing expectations are specifically placed on resins for photoresist for use in fabrication of semiconductors on the order of giga using ArF excimer laser as a light source in exposure process step. However, the ArF excimer laser has a wavelength in the far-ultraviolet region of 193 nm, and resists used must be transparent in the far-ultraviolet region. Some novel resins differing from novolak resins now used have been proposed.
Among them, polycyclic alicyclic monomers each containing a lactone skeleton will exhibit adhesion to substrates when they are polymerized, may have resistance to etching and have received attention in recent times. However, only few proposals have been made on such monomers, for example, in Japanese Unexamined Patent Application Publications No. 2000-26446 and No. 2000-159758. Accordingly, demands are made on development of novel monomers and polymers for photoresist which can exhibit more excellent functions in order to design the best resists.